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Aims: The aim of the current study was to determine the role of Avicennia marina’s primary production as well as other food sources in the diet of Longjaw thryssa, Thryssa setirostris (Broussonet, 1782) in an arid mangrove ecosystem using carbon stable isotopes of carbon (δ¹³C) and nitrogen (δ¹⁵N).
Material & Methods: We collected five potential food sources in the ecosystem including fresh and senescent leaves of Avicennia marina, particulate organic matter, microphytobenthos and sediment organic matter for further stable isotope analysis. Additionally, fishes were collected with a combination of set nets and seines. The muscle tissue (boneless and skinned, 5 g) was removed from the dorsum of fish.
Findings: Significant differences were found between carbon and nitrogen isotopes of different food sources (p < 0.05). Although, this was not significant for green and senescent leaves (p > 0.05). The average values of carbon and nitrogen isotopic ratios of T. setirostris were 15.93‰ and 13.01‰, respectively. The SIMMR model showed that the contribution of senescent and fresh leaves in the diet of T. setirostris was 15% and 10%, respectively.
Conclusion: The result of the current study emphasized a limited role for mangrove detritus in the diet of transient fishes in an arid mangrove ecosystem.
 

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Nowadays, multilayered sheet metals are used in order to achieve a wide range of favorite mechanical, physical, thermal and electrical properties. The laser beam passage over the sheet creates extreme temperature changes which can lead to a change in chemical properties and microstructures. Due to the wide application of these materials in chemical and corrosive environments, corrosion tests were carried out on two-layered SUS304L/copper C11000 and three-layered SUS430/copper C11000/steel SUS430 sheets subjected to various laser passes. Ytterbium fiber laser is used and the governor mechanism during the process is TGM. The changes of microstructures were revealed by metallography. Corrosion resistance of steel layer in three-layered sheet subjected to laser was dropped due to the martensite and oriented ferrite grain size reduction in HAZ. There is no change in microstructure and corrosion behavior of copper layer and the second steel layer due to the HAZ low penetration depth. There is no change in microstructure and corrosion behavior of steel layer in two layered sheet due to the austenitic microstructure. Penetration depth of HAZ in two-layered sheet is limited to a small part of its steel cross section. So, there is no change in microstructure and corrosion behavior of copper, and corrosion is the same all over the copper layer in all specimens.

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In this study, the performance of direct absorption solar collector is experimentally investigated using Fe3O4/Silica hybrid nanofluid based on deionized water. First, stability of prepared nanofluids is considered using spectral absorbency method. Then, spectrophotometry method is used for measuring optical properties of nanofluids. A prototype of this new type of collector was built with applicability for solar water heating systems. The procedure of EN 12975-2 standard was used for testing the thermal performance of the collector. Results show that collector efficiency is enhanced by nanofluid concentration, so that collector maximum efficiency is 73.9%, 79.8% and 83.7%using nanofluid with concentration of 500 ppm, 1000 ppm and 2000 ppm, respec/tively. This vaule is 63% using the base fluid as working fluid. Regarding very low volume fractions of nanofluids used in direct absorption solar collectors, the viscosity of the base fluid experience insignificant increase, therefore, pumping power will not increase significsantly. Such increase in efficiency show that direct absorption solar collector performance using hybrid nanofluid is much better than that of using the water at the same operating conditions. Application of stable hybrid nanofluid results in higher conversion efficiency of solar energy to useful energy.

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In this study, energy and exergy efficiency of residential-type direct absorption solar collector using PVP-coated silver nanofluid has been evaluated experimentally. First, stability and thermophysical and optical properties of nanofluid have been considered using the theoretical and experimental methods. Then, outdoor thermal performance of collector is investigated using the experimental setup based on EN12975-2. Results of energy analysis show that the collector efficiency is increased by increase of flowrate and concentration of nanofluid asymptotically. It is observed that exergy efficiency is firstly increased by nanofluid concentration and then, decreased after reaching the optimum value. The optimum concentration was 500 ppm for all flowrates. The variation of exergy efficiency by reduced temperature difference is similar to volume fraction. The optimum exergy efficiency is obtained at 0.01 m2K/W. The decrease of exergy efficiency by flowrate indicated that exergy losses due to pressure drop have the significant effect on the collector performance.

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In this research, the chemical properties and antifungal effect of Zhumeria majdae essential oil on the molds that cause decay and spoilage of orange fruit during storage were investigated. The hydrodistillation method was used to extract Z. majdae essential oil. The amount of total phenol (according to Folin Ciocalteu method), the amount of total flavonoid (based on the colorimetric method of aluminum chloride), antioxidant effect (based on DPPH and ABTS free radical inhibition methods) and antifungal activity (based on disc diffusion agar, well diffusion agar, minimum inhibitory concentration, and minimum fungicidal concentration) of essential oil against Penicillium italicum and Penicillium digitatum were investigated. The content of total phenol and total flavonoid of the essential oil were equal to 51.38 mg GAE/g and 22.18 mg QE/g, respectively. Z. majdae essential oil was able to inhibit DPPH and ABTS free radicals (61.50% and 67.85%, respectively). The results of the antifungal effect of Z. majdae essential oil showed that the average diameter of the inhibition zone for the fungal strains of P. italicum and P. digitatum in the disc diffusion agar method was 11.10 and 13.70 mm, respectively, and in the well diffusion agar method it was 12.20 and 14.90 mm. The minimum inhibitory concentration for these strains was equal to 4 and 2 mg/ml and the minimum fungicidal concentration was equal to 64 and 16 mg/ml. According to the results, Z. majdae essential oil can be used as a natural antimicrobial agent in order to prevent the growth of fungal strains that cause rot and spoilage of orange fruit during storage.